1. Field of the Invention
The present invention is directed to a new class of 3-aryldihydrouracils. More specifically, the present invention is directed to a class of 3-aryldihydrouracils having utility as pre- and post-emergent herbicides.
2. Background of the Prior Art
Weeds and other undesirable plants undermine the production of useful agricultural crops by inhibiting the production of foliage, fruit or seeds of these useful plants Weeds cause this undesirable result because of their sharing available light, moisture, nutrients and space with useful crops. Indeed, in many cases weeds exclude light, moisture, nutrients and even space to the useful crops with which they interfere. As a result, the presence of weeds not only reduces the quantity and quality of harvested agricultural crops but, in addition, reduces harvesting efficiency. Thus, it is not surprising that weed control is essential for the successful and economic production of many agronomic and horticultural crops including corn (Zea mays L.), cotton (Gossypium hirsutum L.) and peanuts (Archis hypogaea L.).
In addition to the economic necessity of controlling weeds, to ensure efficient production of useful crops, the control of weeds on noncropped areas is also essential. Weeds present a fire hazard. Many weeds give off pollen which cause serious irritation and illness to a significant percentage of the population afflicted with allergies. Moreover, weeds can cause undesirable drifting of sand, snow and the like. Therefore, suppression of undesirable weed growth is not only advantageous in the case of the successful growth of useful crops but, also, is useful even on lands on which useful crops are not grown. For these reasons, although a large number of compounds possessing herbicidal activity are known, there is a continuing need in the art for the identification and use of new and effective additional compounds to control the growth of unwanted vegetation.
Substituted 3-aryluracils are known in the art. Indeed, substituted 3-aryluracils are disclosed as possessing herbicidal activity. European Patent Application Nos. 0195 346 A2 and 0 260 621 A2, both to Wenger et al., disclose two classes of 3-aryluracils useful as herbicidal agents. The compounds of the '346 and '621 applications are uracil compounds, that is, aromatic heterocyclic compounds substituted at the 3-position with substituted phenyl groups. These compounds are structurally removed from aryl substituted saturated heterocyclic compounds.
The above remarks establish the continuing need in the art to develop new and improved herbicides to control undesired vegetation that interferes with the successful production of useful plants as well as negating other adverse effects associated with the uncontrolled growth of weeds and the like. These remarks also establish that the class of compounds, saturated heterocyclic dihydrouracils substituted at the 3-position with substituted aryl represent a class of compounds not known in the art.